The present invention relates to alignment of magnetic resonance (MR) volumes in whole-body MR scans, and more particularly, to automatic alignment of leg-volumes in whole-body MR scans that is insensitive to leg movement.
Magnetic Resonance (MR) is a well known technique for imaging internal structures of a human body. MR scanners are used to scan portions of the human body resulting in MR volume data (MR volume) representing an MR image of the scanned portion of the body. In whole-body MR scanning of a patient, a set of MR volumes covering the whole body of the patient are obtained using multiple scans. It is then necessary to align (or register) the MR volumes to generate a single MR image of the patients body, referred to as a whole-body composition.
United States Patent Application 2006/0052686 presents a method for aligning multiple MR volumes based on overlapping features in the MR volumes. This method uses multi-scale resolutions of the volumes to speed up correlation between the features in the MR volumes. However, this method assumes that the volumes being aligned are rigid. This assumption is typically correct for imaging of the head, torso, and pelvis, but may not always hold for MR volumes of the legs. The time necessary for MR scans of multiple leg-volumes can be in the order of minutes. In this time, in-scan movement of the legs is possible, especially for a patient whose ability to fully control leg movement is impaired. This can lead to misalignment of the legs in the whole-body composition. Accordingly, an alignment method for leg-volumes that is insensitive to leg movement is desirable.